The invention discloses a central overrunning clutching synchronizer gearbox for an electric bicycle. The gearbox comprises a dead axle and a moving axle, wherein the dead axle and the moving axle areindependently provided with multiple levels of gears; the gears on the dead axle and the gears on the moving axle are subjected to constant meshing arrangement one by one; the gears on the moving axle can be rotatably sheathed to the moving axle relative to the moving axle; a spline which carries out axial movement along the moving axle and synchronously operates with the moving axle is installedin the moving axle; the spindle is pulled and driven by a steel wire to move; the gears on the moving axle are independently provided with a spline groove which synchronously operates after the gearsare cooperated with the spline. Each gear on the moving axle corresponds to a tap position, the tap position is changed through the movement of the spline, tap position can be realized through pulling a steel wire even if parking is carried out, and tap position change speed is high. Meanwhile, a constant meshing way is adopted to enable the structure of the gearbox to be compact, small in spaceand convenient in use.